Wire-line suspended electric pump installation in well casing



Nov. 19, 1968 A. ARUTUNOFF 3,411,454

WIRE-LINE SUSPENDED ELECTRIC PUMP INSTALLATION IN WELL CASING Filed March 9, 1967 INVENTOR. ARMA/S ARUTUNOFF a r f 6. ATTORNEY United States Patent M 3,411,454 WIRE-LINE SUSPENDED ELECTRIC PUMP INSTALLATION IN WELL CASING Armais Arutunotf, Bartlesville, Okla, assignor to Reda Pump Company, Bartlesville, Okla., a corporation of Delaware Filed Mar. 9, 1967, Ser. No. 621,924 8 Claims. (Cl. 103219) ABSTRACT OF THE DISCLOSURE A wire-line suspended electric pump installation for use in a well casing, including a pump having a vertical discharge tube opening into the casing and supported by said wire-line which includes electrical conductors. A packer embraces the tube below its discharge opening and seals against the casing. A slip unit having expandible slip members is fixed to the tube between the packer and pump, and includes means responsive to fluid pressure for expanding the slip members to support the weight of the pump and a column of fluid above the packer, relieving longitudinal stress on the cable.

Background of invention conventionally, motor and pump assemblies for oil wells and the like comprise a series of coaxial units arranged in superposed relation, including a pump unit, a motor unit, and a protecting unit, such for example as the general assembly disclosed in my prior Patent No. 2,783,400, issued on Feb. 26, 1957. Ordinarily, the pump unit is aflixed at its upper end to the lower end of a string of tubing which extends within the casing to the earths surface. Liquid is thereby pumped from the lower portion of the casing, through the fluid inlet of the centrifugal pump, and upwardly within the tubing string to the earths surface.

While this system has worked satisfactorily for many years in pumping fluid, a string of tubing is relatively expansive, and, in addition, the lowering of the installation into position and removal thereof for repair of the pump requires strings of tubing to be assembled as the pump is lowered into position and disassembled upon removal from the casing, all of which is time-consuming and expensive.

Summary of invention The present invention is designed to provide means for utilizing a centrifugal pump installation in a casing to force the fluid to the earths surface without the use of a string of tubing. The installation is simply lowered into the casing while suspended on a'wire-line, and, at the proper elevation, locked in position for operation. One problem which has hampered the use of electric pumps suspended on wire-lines is that under conventional concepts, the wire-line is required to support the entire weight of the pump installation, plus the additional weight of the column of fluid in the casing above the pump installation.

It is therefore the primary object of the present invention to overcome this difliculty by providing a slip unit having expandible slip members which is fixed to the pump unit, and including means responsive to the fluid pressure developed by the pump for expanding the slip members into engagement with the casing for supporting the weight of the pump and the column of fluid above the packer, which thereby relieves longitudinal stress on the cable.

The drawings Referring to the drawings in which numerals of like 3,411,454 Patented Nov. 19, 1968 character designate similar parts throughout the several views:

FIG. 1 is a sectional view through a casing, showing a typical motor and pump assembly and slip unit in side elevation;

FIG. 2 is an enlarged sectional view illustrating the packing unit and slip setting unit;

FIG. 3 is a further enlarged sectional view illustrating the slip setting mechanism; and

FIG. 4 is a transverse sectional view taken on line 33 of FIG. 2.

Detailed description Referring first to FIG. 1 of the drawings, 10 represents a conventional well casing which extends from the earths surface into a fluid producing formation. A pump installation comprising an electrically driven centrifugal pump 11, a motor protector 12, and a pump 13, coaxially arranged in superposed relation, is lowered into the casing 10 while suspended from a wire-line or cable 14, running from a suitable winch at the earths surface (not shown). The pump 13 is driven by the motor 1.1 through a coaxial motor shaft extending through the motor protector 12 in the conventional manner.

The means for connecting the wire-line 14 to the pump installation will best be seen from FIG. 2. A pump discharge tube 15, connected to the pump outlet, is threaded as at 16 at its upper end for engagement with complementary threads in the lower extremity of a slip unit, generally indicated at 17, and comprising a generally cylindrical body 18. A vertically extending tube 19, integral with the body 18, communicates with and forms an extension of the pump discharge tube and projects vertically above the body 18 Where it is threadedly connected to a perforated discharge nipple 20 by a coupling 21. The upper extremity of the coupling 21 is threadedlyconnected to a wire-line connecting socket, generally indicated at 22. which firmly secures the entire installation to the lower end of the wire-line or cable 14. The particular construction of this connecting assembly forms the subject matter of another application and will not be described in detail here.

However, it should be stated that the wire-line 14 is of the type comprising an outer layer of preferably spirally-wound supporting wires 14a, and a central core 14b, in which are positioned in spaced relationship a plurality of conductors 140, the lower ends of which are electrically connected to the motor 11.

In the embodiment shown in the drawings, the discharge nipple 20 is provided with a series of radial openings 20a which open into the interior of the casing 10, and the core 14b of the wire-line enters the upper end of the discharge nipple, centrally thereof, and is then directed outwardly through an opening 20b in the upper portion of the nipple, from whence it extends downwardly for connection to the pump.

A packing unit, generally indicated at 23, comprises an annular packer cup thimble 24 which slidably embraces the discharge tube extension 19 above the slip unit 17 and receives a frusto-conical packer cup 25 formed of suitable packing material. The packer cup 25 is annularly recessed at its upper end as at 25a to receive an annular retainer 26 surrounding the tube extension 19 which positions the packer cup with the outer annular surface of its upper edge in sealing contact with the inner surface of the casing 10. The downwardly converging contour of the packer cup permits its sliding movement into the well casing, while the flaring cup causes a sealing action against the casing under the influence of a column of fluid in the casing.

A check valve is preferably located at the upper end of discharge tube extension 19, which is designed to permit freedom of flow for the fluid being pumped upwardly through the system, but to restrict any downward flow upon stopping the pump. Without such a precaution, the weight of a column of fluid in the casing above the packer would result in such a speedy return of the fluid down through the casing as to cause the pump to rotate rapidly in reverse, with possible resultant damage to the unit.

Reverting now to the slip unit 17, the upper portion of the body 18 forms an integral cylindrical cup portion 27 which, together with the adjacent periphery of the tubular extension 19, defines an annular chamber 28, the lower portion of which communicates with the interior of the discharge tube extension 19 by means of ports 29. The upper extremity of the chamber 28 communicates with the casing by means of an outlet port 30, thus placing the chamber in communication with the pump discharge at its lower end and with the interior of the casing at its upper end.

An annular plunger 31 is slidably received within the chamber 28, encircling the tube extension 19 between the inlet ports 29 and the outlet port 30 of the chamber. By means of a series of plunger rods 32, slidably mounted in vertical openings 33 in the body 18, the plunger 31 is connected to a guide ring 34. The guide ring 34 is slidably mounted on the pump discharge tube 15, and by means of a series of radially projecting peripheral lugs 35, it is pivotally connected to a corresponding series of wedge-shaped slips 36 by intermediate links 37. The lower ends of each of the slips 36 are provided with depending lugs 38 so that the pivotal connection of the links 37 to the lugs of the ring 34 and the lugs 38 of the slips, provides a double pivot arrangement which facilitates both vertical and lateral movement of the slips, as will later appear.

The slips 36 are segmental units provided on their outer surfaces with outwardly and downwardly directed teeth 39, and their opposite or inner surfaces are inclined to wedgedly engage complementary surfaces 40 in a corresponding series of inclined, longitudinal grooves or recesses 41, spaced around the periphery of the body 18. As best seen in FIG. 4, the grooves 41 include male dovetail portions 42, and the inclined surfaces of the slips are provided with female dovetail portions 43 so that the slips are slidably retained relative to the body 18 in a manner such that when the guide ring 34 moves downwardly, the slips 36 are radially retracted inwardly to achieve positive clearance with the interior of the casing 10 in which the pump is positioned, and when the ring 34 moves upwardly, the slips are radially projected or expanded into gripping engagement with the inner wall of the casing by the wedge action of the complementary inclined surfaces of the slips and grooves. The retracted and projected positions of the slips are shown in FIG. 3.

Normally, the slips 36 are biased toward their lower or retracted positions by means of coil springs 44 surrounding the respective plunger rods 32 between the bottom of the slip body 18 and the top of the ring 34. Both the inner and outer peripheries of the annular plunger 31 are provided with sealing rings 45 to insure fluid tight engagement between the plunger and the adjacent walls of the tube extension 19 and the chamber 28, respectively. Thus, when the fluid pressure of the pump 11 enters the lower portion of the chamber 28 through ports 29, the plunger 31 is forced upwardly in the chamber which vents into the casing through port 30 and the ring 34 is drawn upwardly, which, in turn, slides the slips 36 upwardly in their grooves, causing a wedging action between the body 18 and the casing 10 to lock the entire installation in place.

As shown in FIG. 1, as a precaution against an excessive rate of descent of the installation in the casing, I may provide an auxiliary slip unit 47 having slip members 47a which per se, forms the subject matter of another application. Briefly, this auxiliary unit is attached to the bottom of the installation and includes two arms 48 carrying rollers 49, the arms being pivotally mounted on a vertically slidable support 47b, connected to the slip members. The arms are normally urged outwardly to bring the rollers into rolling frictional engagement with the inner wall of the casing under the influence of spring means 50. These rollers are provided with radially projectible, weighted members, operable by centrifugal force, so that when the assembly descends at an excessive rate of speed, the centrifugal force of the rollers causes the projectible members to protrude beyond the peripheries of the rollers and engage stop means which prevent further rotation of the rollers. Thus, the rotary frictional engagement of the rollers with the casing is transformed into sliding frictional engagement to act as a brake, causing the slidable support 47b to move upwardly, to thereby set the auxiliary slip members 47a against the casing, preventing further descent of the installation.

Operation The assembly pump installation is lowered into the casing 10 by means of wire-line or cable 14 to the desired depth, and during this operation, the packer 25 slides easily downwardly in the casing, and the slips 36 are retained in retracted positions by the respective springs 44 so that they do not engage the interior wall of the casing.

When the pump installation reaches the desired depth in the well, still suspended by the wire-line 14, the motor 11 is energized through the wire-line and its conductors, which actuates the propellers of the centrifugal pump 13, drawing fluid from the lower portion of the casing through the pump inlet 13a and forcing it upwardly under pressure through the tubing extension 19 and outwardly into the casing through the perforated discharge nipple 20. Fluid under pressure enters the interior of the chamber 28 through inlet ports 29 and forces the plunger 31 upwardly. This upward force is transmitted by plunger rods 32 to the guide ring 34 and is thence transmitted to the wedge slips 36 by the link connections 35, 37 and 38. The slips are thus forced upwardly and outwardly into gripping engagement with the interior of the casing to support not only the weight of the pump installation, but the column of fluid which has been forced into the casing above the packer 25. The weight of the fluid column forces the flaring portion of the packer 25 outwardly into sealing engagement with the interior surface of the casing, and the continued operation of the motor and pump installation advances the column up the interior of the casing to the earths surface.

As the weight of the fluid column increases during its upward advance through the casing, the wire-line 14 will be extended slightly by the additional tension applied thereto in supporting the weight of the fluid. This permits the slip body 18 to move slightly downwardly, forcing the teeth 39 of the slips 36 into increased gripping contact with the casing, which augments the effect of the plunger 31. Thus, the greater the weight of the fluid column above the pump, the more pressure is applied by the slips to hold the weight of the fluid column. In this way, the weight of the fluid column is supported by the slips so that the wire-line 14 is not required to withstand the ti /eight of the fluid column as well as the pump installa- When pumping is terminated, energy is cut off from the conductors 14c, stopping the motor 11 and pump 13. Normally, fluid from the column above the packer will flow in reverse direction, back down through the perforated nipple 20 at a rapid rate of descent. However, by means of the check valve 46, the descent of the column of fluid is restricted to avoid damage to the pump until the total fluid height is equalized and no fluid head load exists above the pump. When pressure equalization occurs in the chamber 28, the springs 44 force the slips 36 downwardly, unlocking them from contacting engagement with the interior of the casing. When the fluid levelin the casing is equalized, the radial pressure on the packer cup 25a against the interior of the casing is likewise diminished, and in this state, the pump installation may be withdrawn from the well as desired by rewinding the wireline 14 at the earths surface.

It will thus be seen that the invention provides a wireline electric bottom-hole pump which can be inserted into and removed from a well casing with a minimum of effort and time. When pumping action is initiated, the pump automatically causes engagement of the slips with the interior of the casingto support the fluid load in such a manner that the load is not supported by the wire-line. The pump automatically releases engagement with the casing when fluid is not being pumped, and the pump provides an arrangement for utilization of centrifugal pumps in a casing without requiring the use of tubing.

From the foregoing, it is believed that the invention may be readily understood by those skilled in the art without further description, it being borne in mind that numerous changes may be made in the details disclosed without departing from the spirit of the invention as set forth in the following claims.

I claim:

1. In a tubingless electric pump installation, including a Well casing, an electric centrifugal pump suspended solely by a Wire-line in said casing, a vertical discharge pipe connected to the upper end of said pump and opening into said well casing above said pump, a slip setting device for said pump, comprising a slip supporting body connected to said pump, at least two radially expandible slip members mounted on the periphery of said body, releasably engageable with the inner wall of said casing, and means responsive to fluid pressure developed by said pump for expanding said slip members into engagement with said casing.

2. A wire-line suspended pump installation for use in a well casing, comprising an electric centrifugal pump unit having a discharge opening at its upper end, a vertical discharge tube connected to said opening and communicating with the interior of said casing, an electric conductive cable connected to the upper end of said tube for suspend ing said pump unit in said casing and energizing said pump installation, a packing unit embracing said tube below its point of fluid communication with said casing, in slidable engagement with the latter, a slip unit aflixed to said tube below said packing unit, including radially expandable slip members releasably engageable with the wall of said casing, and means responsive to fluid pressure developed by said pump unit for expanding said slip members into gripping engagement with said casing, whereby the weight of a column of fluid above said packing unit is supported and longitudinal stress on said wire-line is minimized.

3. An installation as claimed in claim 1, wherein said slip unit comprises a cylindrical body concentrically fixed to said tube, a plurality of tapered slip members disposed for vertical sliding movement in complementary peripheral recesses in said body, a pressure chamber in said body communicating at one end with the discharge opening of said pump, a plunger in said chamber, and means connecting said plunger to said slip members for expanding the latter in response to fluid pressure in said chamber.

4. An assembly as claimed in claim 3, wherein said pressure chamber is in the form of an annulus concentrically surrounding said tube, and said plunger is correspondingly ring-shaped.

5. An assembly as claimed in claim 4, wherein the means connecting the plunger to the slip members com prises a guide ring slidably supported on said tube below said body, means connecting said ring to respective slip members, and connecting rods for securing said ring to said plunger.

6. An assembly as claimed in claim 5, wherein the means connecting said ring to respective slip members comprise links pivotally mounted at one end on said ring and pivotally connected at their opposite ends to respective slip members, to thereby accommodate both vertical and lateral movement of said slip members in expansion and contraction.

7. An installation as claimed in claim 2, including a check valve in said discharge tube designed to permit free upward flow of fluid therethrough when said pump is in operation, but to restrict reverse flow when said pump is stopped.

8. An installation as claimed in claim 2, including an auxiliary slip setting unit operable in response to a predetermined speed of descent of said installation in said casing to set said auxiliary slips.

References Cited UNITED STATES PATENTS 1,941,813 1/1934 Nixon et al. 103-219 2,552,153 5/1951 Crake 1032l9 3,025,800 3/1962 Wolf et al. l032l9 ROBERT M. WALKER, Primary Examiner. 

